During orthopedic implant procedures, e.g. total hip replacement (THR), the orientation of the surgical implants has a direct impact on the postoperative function and long term operability of the implant. Conventional surgical techniques use simple “eyeballing” methods or mechanical tools to position the implant. The “eyeballing” method may be found as being insufficient to provide an accurate alignment of the implant components with the bones where the implant is attached. Studies have shown that sub-optimally positioned orthopedic implants correlate to improper loading, increased implant wear, and even implant failure.
Commercially available computer-assisted surgery systems use tracked tools using optical or magnetic tracking systems. These systems are able to track patient coordinate system accurately and reliably. However, the factors, such as high costs, limited operating range, maintaining a line of sight contact, magnetic interferences, are main issues associated with these technologies.
Inertial sensors have hence been used as tracking technology in computer-assisted surgery. Inertial sensors do not rely on signal transmission and are immune to electromagnetic disturbances during operation. Therefore, inertial sensors are well suited for applications in the OR environment containing a large amount of equipment.